Impact of the COVID-19 pandemic on the trajectory of the number of bronchoscopies performed in a tertiary hospital in Kyoto city.

The coronavirus disease 2019 (COVID-19) pandemic has restricted many medical practices. We aimed to investigate the impact of the COVID-19 pandemic on the number of bronchoscopies, outpatients, and hospital admissions. We retrospectively analyzed the number of outpatients, admissions, and bronchoscopies performed between March 2020 and May 2022. We defined "Peak month of the pandemic," "Wave of the pandemic," "Month in the wave," and "Period of a state of emergency" for each analysis. In the first year of the COVID-19 pandemic, analysis of variance (ANOVA) in linear mixed models indicated significant effects of "month in each wave" on the number of bronchoscopies (P = .003), outpatients (P = .041), and admissions (P = .017). The number of outpatients, admissions, and bronchoscopies was significantly influenced by the first wave of the COVID-19 pandemic. In contrast, in the second year of the COVID-19 pandemic, a mixed-ANOVA indicated significant effects of "month in each wave" only on the number of outpatients (P = .020) but no significant effects on the number of bronchoscopies (P = .407) and admissions (P = .219). During the second year of the pandemic, the number of bronchoscopies and admissions was not significantly affected by the waves of the pandemic. There were no significant differences in the number of admissions and bronchoscopies between the fourth and sixth waves. Although the number of bronchoscopies was found to be significantly affected in the early stages of the COVID-19 pandemic, the impact of the pandemic was much more limited thereafter.

Virological characteristics of the SARS-CoV-2 XBB variant derived from recombination of two Omicron subvariants.

In late 2022, SARS-CoV-2 Omicron subvariants have become highly diversified, and XBB is spreading rapidly around the world. Our phylogenetic analyses suggested that XBB emerged through the recombination of two cocirculating BA.2 lineages, BJ.1 and BM.1.1.1 (a progeny of BA.2.75), during the summer of 2022. XBB.1 is the variant most profoundly resistant to BA.2/5 breakthrough infection sera to date and is more fusogenic than BA.2.75. The recombination breakpoint is located in the receptor-binding domain of spike, and each region of the recombinant spike confers immune evasion and increases fusogenicity. We further provide the structural basis for the interaction between XBB.1 spike and human ACE2. Finally, the intrinsic pathogenicity of XBB.1 in male hamsters is comparable to or even lower than that of BA.2.75. Our multiscale investigation provides evidence suggesting that XBB is the first observed SARS-CoV-2 variant to increase its fitness through recombination rather than substitutions.

Convergent evolution of SARS-CoV-2 Omicron subvariants leading to the emergence of BQ.1.1 variant.

In late 2022, various Omicron subvariants emerged and cocirculated worldwide. These variants convergently acquired amino acid substitutions at critical residues in the spike protein, including residues R346, K444, L452, N460, and F486. Here, we characterize the convergent evolution of Omicron subvariants and the properties of one recent lineage of concern, BQ.1.1. Our phylogenetic analysis suggests that these five substitutions are recurrently acquired, particularly in younger Omicron lineages. Epidemic dynamics modelling suggests that the five substitutions increase viral fitness, and a large proportion of the fitness variation within Omicron lineages can be explained by these substitutions. Compared to BA.5, BQ.1.1 evades breakthrough BA.2 and BA.5 infection sera more efficiently, as demonstrated by neutralization assays. The pathogenicity of BQ.1.1 in hamsters is lower than that of BA.5. Our multiscale investigations illuminate the evolutionary rules governing the convergent evolution for known Omicron lineages as of 2022.

A multicenter study of ocular inflammation after COVID-19 vaccination.

PURPOSE: To report the characteristics of a case series of ocular inflammatory events following COVID-19 vaccination in Japan. STUDY DESIGN: Retrospective multicenter study METHODS: In this retrospective multicenter survey, a questionnaire was sent to 16 Japanese hospitals that had uveitis specialty clinics. Information on patients who developed ocular inflammatory events within 14 days of COVID-19 vaccination between February 2021 and December 2021 was collected. RESULTS: Thirty-seven patients were diagnosed with ocular inflammatory events following COVID-19 vaccination. The mean age was 53.4 ± 16.4 years (range, 26-86 years), and the mean time to onset after vaccination was 6.3 ± 4.2 days (range, 1-14 days). Vogt-Koyanagi-Harada disease (VKH) was the most common event (n = 17 patients, 46%), followed by anterior uveitis (n = 6), infectious uveitis (n = 3), acute zonal occult outer retinopathy (AZOOR) (n = 2), sarcoidosis-associated uveitis (n = 1), acute posterior multifocal placoid pigment epitheliopathy (APMPPE) (n = 1), optic neuritis (n = 1), multiple evanescent white dot syndrome (MEWDS) (n = 1), Posner-Schlossman syndrome (n = 1), and unclassified uveitis (n = 4). Twenty-eight cases occurred after BNT162b2 vaccination (Pfizer-BioNTech) and 8 after mRNA-1273 vaccination (Moderna), whilst 1 patient had no information about vaccine type. CONCLUSIONS: COVID-19 vaccination can be related to various types of ocular inflammatory events. When we encounter patients with ocular inflammatory disease, we should consider that it may be an adverse effect of COVID-19 vaccination.

The Influence of the COVID-19 Outbreak on the Lifestyle of Older Patients With Dementia or Mild Cognitive Impairment Who Live Alone.

Background: Under the COVID-19 outbreak, the Japanese government has strongly encouraged individuals to stay at home. The aim of the current study was to clarify the effects of the COVID-19 outbreak on the lifestyle of older adults with dementia or mild cognitive impairment (MCI) who live alone. Methods: Seventy-four patients with dementia or MCI aged ≥65 years, who regularly visited the dementia clinic of the Department of Psychiatry, Osaka University Hospital, were recruited in this study. The patients were divided into two groups according to their living situation: living alone group (n = 12) and living together group (n = 62). Additionally, the spouses of patients aged ≥65 years were assigned to the healthy control group (n = 37). Subjects' lifestyle changes were evaluated between April 8 and 28, 2020. Results: No subjects with acquaintances or relatives were infected with COVID-19 within the study period. The proportion of subjects who reduced going out in the living alone group, living together group and healthy control group was 18.2, 52.5, and 78.4%, respectively. The proportion of subjects who went out less frequently was significantly lower in both the living alone (p < 0.01) and living together (p < 0.05) groups than in the healthy control group. Conclusion: Most patients with dementia or MCI who live alone did not limit their outings or activities during the COVID-19 outbreak. Regular monitoring for potential COVID-19 infection in people living alone with dementia is vital for their safety and well-being.

Virological characteristics of the SARS-CoV-2 Omicron BA.2.75 variant.

The SARS-CoV-2 Omicron BA.2.75 variant emerged in May 2022. BA.2.75 is a BA.2 descendant but is phylogenetically distinct from BA.5, the currently predominant BA.2 descendant. Here, we show that BA.2.75 has a greater effective reproduction number and different immunogenicity profile than BA.5. We determined the sensitivity of BA.2.75 to vaccinee and convalescent sera as well as a panel of clinically available antiviral drugs and antibodies. Antiviral drugs largely retained potency, but antibody sensitivity varied depending on several key BA.2.75-specific substitutions. The BA.2.75 spike exhibited a profoundly higher affinity for its human receptor, ACE2. Additionally, the fusogenicity, growth efficiency in human alveolar epithelial cells, and intrinsic pathogenicity in hamsters of BA.2.75 were greater than those of BA.2. Our multilevel investigations suggest that BA.2.75 acquired virological properties independent of BA.5, and the potential risk of BA.2.75 to global health is greater than that of BA.5.

Virological characteristics of the SARS-CoV-2 Omicron BA.2.75 variant

The SARS-CoV-2 Omicron BA.2.75 variant emerged in May 2022. BA.2.75 is a BA.2 descendant but is phylogenetically distinct from BA.5, the currently predominant BA.2 descendant. Here, we show that BA.2.75 has a greater effective reproduction number and different immunogenicity profile than BA.5. We determined the sensitivity of BA.2.75 to vaccinee and convalescent sera as well as a panel of clinically available antiviral drugs and antibodies. Antiviral drugs largely retained potency but antibody sensitivity varied depending on several key BA.2.75-specific substitutions. The BA.2.75 spike exhibited a profoundly higher affinity for its human receptor, ACE2. Additionally, the fusogenicity, growth efficiency in human alveolar epithelial cells, and intrinsic pathogenicity in hamsters of BA.2.75 were greater than those of BA.2. Our multilevel investigations suggest that BA.2.75 acquired virological properties independent of BA.5, and the potential risk of BA.2.75 to global health is greater than that of BA.5. Graphical Saito and G2P-Japan Consortium et al. elucidate the virological properties of SARS-CoV-2 Omicron BA.2.75 variant. BA.2.75 is more transmissible than BA.5, and exhibits different antigenicity than BA.2 and BA.5. The BA.2.75 spike exhibits higher affinity to ACE2 and higher fusogenicity, and BA.2.75 is more pathogenic than BA.2 in hamsters.

Virological characteristics of the SARS-CoV-2 Omicron BA.2 subvariants, including BA.4 and BA.5.

After the global spread of the SARS-CoV-2 Omicron BA.2, some BA.2 subvariants, including BA.2.9.1, BA.2.11, BA.2.12.1, BA.4, and BA.5, emerged in multiple countries. Our statistical analysis showed that the effective reproduction numbers of these BA.2 subvariants are greater than that of the original BA.2. Neutralization experiments revealed that the immunity induced by BA.1/2 infections is less effective against BA.4/5. Cell culture experiments showed that BA.2.12.1 and BA.4/5 replicate more efficiently in human alveolar epithelial cells than BA.2, and particularly, BA.4/5 is more fusogenic than BA.2. We further provided the structure of the BA.4/5 spike receptor-binding domain that binds to human ACE2 and considered how the substitutions in the BA.4/5 spike play roles in ACE2 binding and immune evasion. Moreover, experiments using hamsters suggested that BA.4/5 is more pathogenic than BA.2. Our multiscale investigations suggest that the risk of BA.2 subvariants, particularly BA.4/5, to global health is greater than that of original BA.2.

MDA5 Governs the Innate Immune Response to SARS-CoV-2 in Lung Epithelial Cells.

Recent studies have profiled the innate immune signatures in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and suggest that cellular responses to viral challenge may affect disease severity. Yet the molecular events that underlie cellular recognition and response to SARS-CoV-2 infection remain to be elucidated. Here, we find that SARS-CoV-2 replication induces a delayed interferon (IFN) response in lung epithelial cells. By screening 16 putative sensors involved in sensing of RNA virus infection, we found that MDA5 and LGP2 primarily regulate IFN induction in response to SARS-CoV-2 infection. Further analyses revealed that viral intermediates specifically activate the IFN response through MDA5-mediated sensing. Additionally, we find that IRF3, IRF5, and NF-κB/p65 are the key transcription factors regulating the IFN response during SARS-CoV-2 infection. In summary, these findings provide critical insights into the molecular basis of the innate immune recognition and signaling response to SARS-CoV-2.